They are great machines, but "collectable?" well, if you want a lot of Singers, then you should have this one. However they aren't what I would consider an investment like some collectables would be. If you really want "collectable" machines that have long term value as a collectable, you need to go after the early types - mostly pre-high arm machines.
About 95% of the value of a Singer 201-2 is in it's usability. Now, if you stumble upon a 201 Hand crank- that one does have more value as a collectable machine than as a user.